1. Field of the Invention
The present invention relates to a sheet cutting apparatus which cuts a portion of a sheet, and more particularly, to a sheet cutting apparatus which cuts a portion of a bundle of a plurality of coupled sheets.
2. Description of the Related Art
Conventionally, a sheet cutting apparatus which cuts one ends of a sheet bundle in which central portions of a plurality of sheets are bound and they are folded into two at the coupling position to enhance the outward appearance is widely known as disclosed in Japanese Patent Application Laid-open No. 2000-198613.
The conventional sheet cutting apparatus conveys a sheet bundle whose central portions are bound is conveyed to between an upper cutting blade and a lower cutting blade, the upper cutting blade is lowered to the lower cutting blade, and cuts one ends of the sheet bundle located therebetween. Cut pieces generated by cutting the sheet bundle fall due to their own weights and are accommodated in an accommodating box located below the cut piece.
A rocking guide which guides the sheet bundle onto the lower cutting blade is provided above the accommodation box. The rocking guide guides the sheets to the lower blade when the sheet bundle passes, but when cutting, the rocking guide rocks and lowers and retreats so as not to hinder the falling motion of the cut pieces into the accommodation box. When the cutting is completed, the rocking guide again rocks and moves upward and guides the next sheet bundle.
The sheet bundle which is cut as described above is then conveyed to a batch accommodating portion (not illustrated) and accommodated therein.
In the conventional sheet cutting apparatus, a cut piece falls into the accommodation box by its own weight, but when the cut piece receives external resistance such as static electricity, air resistance and sliding resistance, the cut piece can not fall into the accommodation box in some cases. If the cut piece can not fall while the rocking guide is lowering (retreating), the rocking guide again moves upward and a path to the accommodation box is cut off. Therefore, even if the cut piece falls thereafter, the cut piece remains on the rocking guide. Such a phenomenon is prone to occur when the cut piece is light in weight or when the width of the cut piece (in the sheet conveying direction) is set short.
If a new sheet bundle is conveyed in a state where a cut piece remains on a convey path of a sheet bundle, the cut piece is conveyed together with the sheet bundle and is accommodated in the batch accommodating portion. If a cut piece is placed in the batch accommodating portion in which only bindings should be accommodated, this degrades dignity.
If a cut piece moves on the convey path, there is a deficiency that a sensor in the convey path erroneously detects.
To reliably accommodate a cut piece in the accommodating box, it is contemplated that another means such as air injection is newly provided, but this makes the structure complicated, the apparatus is increased in size and costs.
It is an object of the present invention to provide a sheet cutting apparatus having a simple structure and capable of avoiding a case in which a cut piece of a sheet does not fall and remains on a convey path.